Sr_(2)ReNbO_(6)双钙钛矿电子结构及性质的第一性原理研究  

First-principles Study of the Electronic Structure and Properties of Double Perovskite Sr_(2)ReNbO_(6)

作　　者：张传成 丁守军 刘文鹏 邹勇[1] 胡海棠 王苗苗 宿文志[1] ZHANG Chuancheng;DING Shoujun;LIU Wenpeng;ZOU Yong;HU Haitang;WANG Miaomiao;SU Wenzhi(School of Microelectronics&Data Science,Anhui University of Technology,Maanshan 243032,China;Advanced Laser Technology Laboratory of Anhui Province,Hefei 230037,China;Anhui Institute of Optics and Fine Mechanics,HFIPS,Chinese Academy of Sciences,Hefei 230026,China)

机构地区：[1]安徽工业大学微电子与数据科学学院,安徽马鞍山243032 [2]先进激光技术安徽省实验室,合肥230037 [3]中国科学院合肥物质科学研究院安徽光学精密机械研究所,合肥230026

出　　处：《安徽工业大学学报（自然科学版）》2024年第6期583-593,共11页Journal of Anhui University of Technology（Natural Science）

基　　金：国家自然科学基金项目(52202001);安徽省科技重大专项(202203a05020002);安徽省高校自然科学基金项目(KJ2021A0388);先进激光技术安徽省实验室开放研究基金项目(AHL2021KF07)。

摘　　要：基于密度泛函理论(DFT),采用Perdew–Burke–Ernzerhof交换关联势的PBEsol–GGA泛函优化Sr_(2)ReNbO_(6)(Re=La,Gd,Lu)双钙钛矿晶体的结构,获得最低能量的稳定结构。以优化的结构为模型,计算Sr_(2)ReNbO_(6)(Re=La,Gd,Lu)晶体的能带结构和态密度(DOS)、复介电函数ε(ω)、折射率n(ω)、反射率R(ω)及消光系数k(ω)等光学特性指标,分析入射光子能量对材料光学特性的影响;计算Sr_(2)ReNbO_(6)(Re=La,Gd,Lu)晶体的弹性常数Cij,并由Cij进一步获得杨氏模量(Y)、体积模量(B)、剪切模量(G)和泊松比(χ)等机械特性指标,分析晶体结构对材料机械特性的影响。结果表明:优化双钙钛矿晶体结构获得的晶格常数与现有的实验值吻合较好;Sr_(2)ReNbO_(6)(Re=La,Gd,Lu)材料的能带结构呈现半导体特性,其中立方结构的Sr_(2)LaNbO_(6)带隙宽度为3.12 eV,且为直接带隙,而单斜结构的Sr_(2)GdNbO_(6)和Sr_(2)LuNbO_(6)为间接带隙,带隙宽度分别为3.25,3.29 eV;Sr_(2)ReNbO_(6)(Re=La,Gd,Lu)的最大反射率R(ω)分别为32.8%,29.3%,33.0%,在紫外区域存在较大的吸收系数;Sr_(2)ReNbO_(6)(Re=La,Gd,Lu)的泊松比χ分别为0.27,0.28,0.27,均位于0.25附近,该系列材料的原子更倾向于以离子键的形式结合,表现出一定的柔韧性。Based on the density functional theory(DFT),the Perdew–Burke–Ernzerhof exchange-correlation potential was used to optimize the geometry of double perovskite Sr_(2)ReNbO_(6)(Re=La,Gd,Lu)crystals,and the stable structures with lowest energy were obtained.Using the optimized structure as a model,density of states(DOS),optical properties contain complex dielectric constantε(ω),refractive index n(ω),reflectivity R(ω)and distinction coefficient k(ω)of Sr_(2)ReNbO_(6)(Re=La,Gd,Lu)crystals were calculated,and the influence of incident photon energy on the optical properties of the material was analyzed.The elastic constants Cij of Sr_(2)ReNbO_(6)(Re=La,Gd,Lu)crystals were also calculated,according to the Cij,the mechanical properties include Young’s modulus(Y),bulk modulus(B),shear modulus(G)and Poisson’s ratio(χ)were further obtained,and the influence of crystal structure on the mechanical properties of the material was investigated.The results show that the lattice constants obtained from optimizing double perovskite crystal structure are in agreement with the available experimental values.The band structure of Sr_(2)ReNbO_(6)(Re=La,Gd,Lu)materials exhibits the semiconductor characteristics,and the cubic Sr_(2)LaNbO_(6) exhibits a direct band structure with bandgap of 3.12 eV,whereas the monoclinic Sr2GdNbO6 and Sr_(2)LuNbO_(6) exhibit indirect band structure with bandgap of 3.25 eV and 3.29 eV,respectively.The maximum reflectivity R(ω)of Sr_(2)ReNbO_(6)(Re=La,Gd,Lu)are 32.8%,29.3%,33.0%,respectively,with a significant absorption coefficient in the ultraviolet region.The Poisson’s ratio(χ)of Sr_(2)ReNbO_(6)(Re=La,Gd,Lu)crystals are 0.27,0.28,0.27,respectively,all close to 0.25.The atoms in this series materials are probe to bond ionically,exhibiting a certain degree of flexibility.

关 键 词：双钙钛矿 第一性原理计算 电子结构 光学性质 机械特性 太阳能电池 

分 类 号：O731[理学—晶体学] O733O734